Morin inhibits interleukin-1β-induced nitric oxide and prostaglandin E2 production in human chondrocytes.

It is well known that the inflammatory cytokines play important roles in osteoarthritis (OA). In the present study, we investigated the anti-inflammatory properties of morin in chondrocytes. The nitric oxide (NO) production was determined by Griess method, the prostaglandin E2 (PGE(2)) production was detected by Enzyme-linked immunosorbent assay (ELISA). The expression of inducible NO synthase (iNOS) and cyclooxygenase (COX)-2 were investigated by quantitative real-time PCR and western blot. In addition, western blotting and immunofluorescence staining were performed to investigate the protein level of inhibitor of nuclear factor-κB (IκB-α) and the translocation of nuclear factor kappa B (NF-κB). For the in vivo study, morin was administered by intra-articular injection in rats, and the gene expression of iNOS and COX-2 was assessed. We showed that morin inhibited the production of NO and PGE(2) as well as the expression of iNOS and COX-2 in interleukin-1-beta (IL-1β)-induced chondrocytes. In addition, morin suppressed the degradation of IκB-α as well as the translocation of NF-κB. In vivo study, morin exerted anti-inflammatory properties in an IL-1β-induced rat OA model. Our data suggest that morin possess potential value in the treatment of OA.